Molybdenum disilicide

Many metals form conductive silicides, which, like SiC, are resistant to oxidation through the formation of stable passivating layers of silicates or silica on their surfaces at high temperatures. Molybdenum disilicide (MoSi2) has been developed as a heating element for use in air at temperatures above 1500 °C. Its resistivity behaves as is expected for a metal, increasing from about 2.5 x 10-7 fim at room temperature to about 4 x 10-6 Qm at 1800 °C. 

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Several coating techniques are now available to overcome the oxidation problems with molybdenum above 300°C. One of these, based on molybdenum disilicide, is finding increased usage in flame breakout shields for aero-engines where tests have shown (unpublished work) that the coated material can withstand a high pressure torching type flame attack at temperatures in excess of 2(X)0°C. 

Borides and Silicides. These materials do not show good resistance to oxidation. Some silicides, however, form Si02 coatings upon heating which retards further oxidation. Molybdenum disilicide [1317-33-5]> MoS, is used widely, primarily as an electrical heating element. 

Nickel aluminide (NiAl, Ni3AI), titanium aluminide (TiAl, Ti3AI), molybdenum disilicide (MoSi2)... 

Carrillo-Heian, E.M., Carpenter, R.D., Paulino, G., Gibeling, J.C., Munir, Z. (2001), Dense layered molybdenum disilicide-silicon carbide functionally graded composites formed by field-activated synthesis , J. Am. Ceram. Soc., 84, 962-968. 

The use of synergists (micro- and nanoparticles) was also investigated in intumescent coatings. The most recent work conducted is based on the studies done in intumescent bulk polymer (see reaction to fire part). Li et al.108 suggested combining EG and/or molybdenum disilicide (MoSij) in an intumescent system based on APP/PER-melamine. The results show that incorporating the... 

Both metals are inert to oxygen at ordinary temperatures, but at red heat they combine with it readily to give the trioxides. They both combine with chlorine when heated, but even at room temperature they are attacked by fluorine, yielding the hexafluorides. The metals also react on heating with B, N, and Si. Molybdenum disilicide (MoSi2) is used in resistance heating elements, and WC is used to tip cutting tools. 

Intermet allies Nickel aluminide (NiAl, NijAl) Titanium aluminide (TiAl, TijAl) Molybdenum disilicide (MoSi )... 

Molybdenum disilicide is made by direct synthesis of elements in a powdered mixture. Forming (e.g. from plastic mass containing an organic plasticizer) is followed by sintering at 1600—1700 °C the last stage of sintering may be effected by direct resistance heating. 

Molybdenum disilicide is utilized for the manufacture of electrical heating elements, which can be operated in air at temperatures up to 16()0°C... 

Molybdenum disilicide stands out and is utilized in electrical heating elements, which can be operated at temperatures of up to 1600°C in air due to the formation of Si02 layers on surface. 

Use Electrical resistors, protective coatings at high temperatures, engine parts in space vehicles (molybdenum coated with molybdenum disilicide). 

E. Fitzer, W. Remmele Possibilities and Limits of Metal Reinforced Refractory Silicides, Especially Molybdenum Disilicides", Fifth International Conference on Composite Materials, AIME, 1985, p. 515. 

It should be noted that the mentioned molybdenum disilicide is a borderline case of the intermetallics since silicon is not a metal, but a semiconductor. It is known that the combination of silicon with metals gives rise to compounds with metallic properties, e.g. MoSij, as well as compounds with semiconductor properties (Nowotny, 1963), i.e., silicides mark the transition from intermetallics to compounds of metals and nonmetals. Nevertheless, silicides are traditionally included in the field of intermetallics because of their many similarities with metals (Wehrmann, 1967). 

Which of the following materials could be classified as a ceramic. Justify your answer, (a) Solid argon (Ar) (b) molybdenum disilicide (MoSi2) (c) NaCl (d) crystalline sulfur (S) (e) ice (f) boron carbide (B4C). 

S. Bose, Engineering Aspect of Creep Deformation of Molybdenum Disilicide, m ... 

Figure 5.14. Part of the phase diagram of Si/Mo indicating possible reaction paths (arrows) of reactive liquid phase sintering of molybdenum disilicide. If the reaction heat increases the temperature the solid does not form during sintering and the whole mixture melts.

Kink nucleation on partial dislocations has also been considered [27] because of the experimental observation that the critical resolved shear stress for 110 (111) slip in molybdenum disilicide decreases when substitutional alloying elements are added that decrease the stacking fault energy, and increases when substitutional elements are added that increase the stacking fault energy. This modification may apply not only to other intermetallics but also to ceramics such as spinel, where increasing... 

Molybdenum disilicide (MoSi2), an intermetallic compound, a silicide of molybdenum, is a refractory ceramic primarily used in heating elements. It has... 

Molybdenum Disilicide (MoSi2) tetragonal, D4jjl7 space group isomorphous with WSi2 a=3.197-3.20A c=7.85-7.871... 

Silicides Molybdenum Disilicide (MoSi2) Tungsten Disilicide (WSi2) 6.24- 6.29 9.25- 9.3... 

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